Skeletons last 40 seconds without Skeletal Longevity. Make sure you research Skeletal Longevity to gain an additional 15 seconds, making
Skeleton Warriors last as much as 55 seconds.

You can build Graveyards, which produce corpses, and place Necromancers around them. When you are being attacked you can use the Necromancers
to raise the Corpses to provide Skeleton Warriors to defend the town.

You can use the Meat Wagon to pick up corpses and carry them into battle. Unload the Corpses, then use Necromancers to raise them into
Skeleton Warriors.

There is a maximum limit of 25 Skeleton Warriors that can be summoned by a player.

Be sure to research melee and armor upgrades to make the Skeleton Warriors more effective.

Skeleton Counters
Use spells such as Dispel Magic, Abolish Magic, Purge, and Detonate to cause severe damage
to Skeletons since they are summoned units.

Run away from the Skeletons, the timer will run out and they will die.